E F Johnson Company 2422001-1 Benutzerhandbuch
ALIGNMENT AND TEST PROCEDURES
7-13
August 2000
Part No. 001-2001-200
3. Adjust R236 for 2.8V RMS.
4. Re-adjust the RF generator output for 12 dB
SINAD.
5. Press the space bar to key the transmitter.
6. SINAD should not degrade more than 1 dB or to no
less than 11 dB SINAD.
7. Press the space bar to unkey the transmitter.
Receiver Miscellaneous Tests (Optional)
Several additional tests may be performed on the
Repeater Receiver as listed below:
•
Signal Displacement Bandwidth
•
Adjacent Channel Rejection
•
Offset Channel Selectivity
•
Intermodulation Rejection
•
Spurious Rejection
•
Audio Response
•
Audio Sensitivity
Perform the Test desired using the appropriate RF
Generators, modulation frequencies and levels, RS-
232 levels and test probes following the latest TIA
document measurement procedures.
232 levels and test probes following the latest TIA
document measurement procedures.
7.4.5 TRANSMIT AUDIO/DATA LEVEL ADJUST-
MENTS
NOTE: All audio generators and audio voltmeters are
unbalanced unless specifically stated otherwise.
unbalanced unless specifically stated otherwise.
Audio Deviation Limit Adjustment
1. On the MAC, apply a 1 kHz tone at -3 dBm
(578 mV RMS) to P100, pin 32.
2. Insert test cables into J100/J103 and connect to an
AC voltmeter.
3. Press the space bar to key the transmitter.
4. Adjust R305 for 0 dBm (775 mV RMS).
5. Press the space bar to unkey the transmitter.
6. On the MAC, apply a 1 kHz tone at +7 dBm (1.73V
RMS) to P100, pin 32.
(Set modulation analyzer LPF to 3 kHz.)
(Set modulation analyzer LPF to 3 kHz.)
7. Press the space bar to key the transmitter.
8. Adjust U149 with the PgUp/PgDn and CurUp/
CurDn keys to set the maximum allowed deviation
at
at
±
3.5 kHz deviation, 25 kHz channels
(±1.6 kHz 12.5 kHz channels).
9. Press the space bar to unkey the transmitter.
10.Remove the signal from P100, pin 32.
Repeat Audio Level Adjustment
NOTE: Audio Deviation Limit Adjustment must be
completed before this test.
completed before this test.
1. Adjust the RF generator for 100
µ
V into the
receiver with a 1 kHz tone at
±
1.5 kHz deviation,
25 kHz channels (±800 Hz 12.5 kHz channels).
Be sure the Modulation Analyzer LPF switch is set
to 3 kHz.
Be sure the Modulation Analyzer LPF switch is set
to 3 kHz.
2. Press the space bar to key the transmitter.
3. On the MAC, adjust R237 to achieve
±
1.5 kHz
(
±
100 Hz) transmit deviation, 25 kHz channels,
(±800 Hz 12.5 kHz channels). Be sure the modula-
tion analyzer LPF switch is set to 3 kHz.
tion analyzer LPF switch is set to 3 kHz.
4. Press the space bar to unkey the transmitter.
5. Connect an AC voltmeter to J103 and P100, pin 31
(RX_VOICE).
6. Adjust R238 for -3 dBm (548 mV RMS).
7. Remove the RF generator from the Receiver.